RU2250196C2 - Method for hydrochemical processing of alunite ore containing silica in the form of amorphous modifications - Google Patents

Abstract

FIELD: nonferrous metallurgy.

SUBSTANCE: alunite ore containing silica in the form of amorphous modifications is subjected to alkaline hydrochemical treatment including crushing to fineness -3 mm and one-step leaching of agitated crushed ore with alkali-aluminate solution for 1-2 h at 60-70°C.

EFFECT: simplified equipment and process flowsheet including recovery of silica, and reduced loss of alkali with refuse slime.

2 ex

Description

The invention relates to ferrous metallurgy, and specifically to the technology of complex processing of alunite raw materials.

The closest known prototypes of the proposed method for the hydrochemical processing of alunite ore are methods of processing alunite ore according to the author's certificate No. 1834248 of March 5, 1990 and the patent of the Russian Federation No. 2036839 of 02/07/92, including crushing of alunite ore to a particle size of minus 7 mm, leaching of crushed ores by the percolation method in two stages, characterized in that in order to increase the extraction of alumina and alkalis into the aluminate solution from alunite; reduction of the specific flux of solutions and heat and energy costs in the technological cycle, the leaching of crushed ore is carried out in countercurrent leaching fluid to alunite in two stages, the first stage of leaching being carried out at t = 70-90 ° С with an alkaline-aluminate solution with a caustic module of 2.6-3, 0 for 1-2 hours until the caustic module of the obtained aluminate solution reaches 1.8-1.65, and the leaching of the solid precipitate in the second stage is carried out for 2-3 hours with an alkaline aluminate solution with a caustic module m 4.3-3.8 to reduce the caustic module of the solution after leaching to 3.0-2.6, followed by its supply to the first stage of leaching of the original ore. These known methods of hydrochemical processing of alunite ore are unsuitable for the processing of alunite ores containing silicon oxide in the form of amorphous modifications, since in the process of leaching crushed ore in two stages with long-term contact of the ore with a high-temperature aluminate solution, amorphous silicon oxide actively interacts with the aluminate solution with precipitation of sodium hydroaluminosilicate in an insoluble form, which leads to large secondary chemical losses of caustic alkali and alumina niya with dump slurry. This also reduces the chemical extraction of alumina from alunite ore into the solution due to overgrowth of alunite capillaries in the crushed ore with sodium hydroaluminosilicate, which precipitates from the aluminate solution.

An object of the invention is to increase the chemical extraction of alumina from alunite ore into the solution and to reduce the secondary chemical losses of caustic alkali and alumina from the aluminate solution into the slurry ore residue.

The problem is achieved in that in the method of hydrochemical processing of alunite ore containing silicon oxide in the form of amorphous modifications, including crushing of alunite ore and leaching of crushed ore with an alkaline-aluminate solution, the alunite ore is crushed to a minus three millimeters before leaching and the leaching is carried out using a crushed ore method using a crushed ore one stage for 1.0-2.0 hours at a solution temperature of 60-70 ° C.

Crushing the ore before leaching to a fineness of more than three millimeters leads to a decrease in the extraction of aluminum oxide from the ore into the aluminate solution.

Reducing the size of crushed ore to less than three millimeters allows the process of leaching of alunite ore to be carried out by the propaganda method in one stage. Reducing the duration of the ore leaching process less than one hour leads to a decrease in the extraction of aluminum oxide from the ore into the aluminate solution. An increase in the duration of the process of leaching of crushed ore more than two hours leads to an increase in the dissolution of amorphous silicon oxide in an aluminate solution. A decrease in the temperature of the aluminate solution below 60 ° C leads to a decrease in the equilibrium dissolution of sulfate salts of alkali in the aluminate solution and to a slowdown in the kinetics of the transition of alumina from ore to aluminate solution.

An increase in the temperature of the aluminate solution during the leaching of crushed ore above 70 ° C leads to an increase in the dissolution of amorphous silicon oxide in the aluminate solution and to a subsequent increase in secondary chemical losses of alkali and aluminum oxide with sludge residue.

Below are the results of experiments on the practical implementation of the method of hydrochemical processing of alunite ore containing silicon oxide in the form of amorphous modifications. For the experiments, we used a sample of alunite ore taken at the Shopane deposit in Turkey containing up to 30% amorphous silicon oxide. For comparison, the experiments of leaching samples of alunite ore were carried out under the conditions of the known and proposed methods.

A sample of alunite ore had the following chemical composition in weight percent:

SiO ₂ Al ₂ O _{3 al.} Al ₂ About _{3 kaol.} Na ₂ O K ₂ O SO ₃ 51.0 14.0 4.7 0.15 4.6 14.6

where Al ₂ O _{3 al.} - alumina in alunite.

Al ₂ About _{3 kaol.} - alumina in kaolin.

1. The experiments on the leaching of an ore sample in a known manner were carried out under the following conditions:

- the ore was crushed to a particle size minus 7 mm,

- leaching of crushed ore was carried out by the percolation method in succession in two stages at a solution temperature of 85 ° C with a duration of 1.5 hours in the first stage and 3.0 hours in the second stage;

- the chemical composition of the initial solution in the first stage of leaching of ore:

Na ₂ O - 107 g / l, Al ₂ O ₃ - 56 g / l, α _k - 3.2;

- the chemical composition of the solution obtained after the first stage of leaching:

Na ₂ O _k - 97 g / l, Al ₂ O ₃ - 88 g / l, α _k - 1.80;

- the chemical composition of the feed solution to the second leaching step: Na ₂ O - 119 g / l, Al ₂ O ₃ - 41.5 g / l, α _k - 4.7;

- the chemical composition of the solution obtained after the second stage of leaching:

Na ₂ O - 116 g / l, Al ₂ O ₃ - 53 g / l, α _k - 3.6;

- the chemical composition of the washed sludge obtained after the second stage of leaching of ore in weight percent:

SiO ₂ Al ₂ O _{3 al.} Al ₂ O _{3 kaol.} Na ₂ O K ₂ O SO ₃ 70.0 5.2 6.45 2.1 1,2 3.6

- chemical extraction from alunite ore into an aluminate solution:

Al ₂ O _{3 al.} - 73%, SO ₃ - 82%;

- specific consumption of alunite ore per 1 ton of aluminum oxide extracted into the solution by leaching the ore in a known manner - 9.8 tons;

- chemical losses with sludge per one ton of alumina recovered in solution:

Na ₂ O - 149 kg, K ₂ O - 85 kg.

2. The experiments on leaching of an ore sample by the proposed method were carried out under the following conditions:

- ore crushed to a particle size minus 3 mm;

- leaching of crushed ore was carried out in one stage by the propagation method at a solution temperature of 70 ° C with a duration of 1.5 hours;

- the chemical composition of the initial solution for leaching of the ore sample: Na ₂ O _to - 119 g / l, Al ₂ O ₃ - 41.5 g / l, α _to - 4.7;

- the chemical composition of the solution obtained after leaching of the ore sample:

Na ₂ O _k - 85 g / l, Al ₂ O ₃ - 7.8 g / l, α _k - 1.80;

- the chemical composition of the washed sludge obtained after leaching of the ore sample, in weight percent:

SiO ₂ Al ₂ O _{3 al.} Al ₂ O _{3 kaol.} Na ₂ O K ₂ O SO ₃ 80.0 0.7 7.3 0.15 0.34 0.9

- chemical extraction from alunite ore into an aluminate solution:

Al ₂ O ₃ - 97%; SO ₃ - 99%.

- specific consumption of alunite ore per ton of aluminum oxide extracted into the solution by leaching of ore by the proposed method - 7.3;

- chemical losses with sludge per one ton of alumina recovered in solution:

Na ₂ O - 7.0 kg; K ₂ O - 15.8 kg.

Claims (1)

A method for the hydrochemical processing of alunite ore containing silicon oxide in the form of amorphous modifications, including crushing alunite ore and leaching the crushed ore with an alkali-aluminate solution, characterized in that the alunite ore is crushed to a particle size of minus three millimeters before leaching and the leaching of the crushed ore into agglomeration is carried out using one method during 1.0-2.0 hours at a solution temperature of 60-70 ° C.